Let the set of ordered pairs (x, y)= {(1, 2), (2, 4), (1, 3), (3, 4)} is a relation between x and
y.

Then the relation:

A. is a function
B. is not a function as y = 4 is related to two values of x i.e. x = 2 and x = 3
C. is not a function as x = 1 is related to two values of y i.e. y = 2 and y = 3
D. is a function except at the point x = 2